This invention relates to a resinous molded part, and more particularly, to a corner structure thereof.
Generally, in the resinous molded part, there is existing a problem of shrinkage thereof after molding. For example, in case of a substantially C-shaped electrical connector having a base portion and a pair of lever portions connected with both ends of the base portion to extend perpendicularly thereto, respectively, there is a possibility that the lever portions are inclined inwardly so that a distance therebetween are shorter than a predetermined dimension. Consequently, there would be raised a problem that the connector shrunk in this way cannot satisfy various functions required as the complete electrical connector. It should be noted that the reason why the lever portions are so inclined is that both of the lever portions are urged inwardly to approach to each other because of differential shrinkage. Thus, as the part cools to room temperature, shrinkage rates vary throughout the part depending upon the local thickness of the part. In the above-mentioned connector, since a thickness of the part at corners where the respective lever portion connects with the base portion is particularly large in comparison with the other portions, a shrinkage rate of an inside of each corner is apt to be larger than that of an outside thereof.
In order to reduce such differential shrinkage therebetween, U.S. Pat. No. 4,430,370, which is relevant to Japanese Unexamined Patent Publication (Kokai) No.57-201635, discloses a resinous molded part provided at each corner with a groove to decrease a thickness of the part thereof. However, in case that the grooves are respectively provided at the corners of the part in this way, it would have a disadvantage that the strength of the part is lowered at the corners.